Emergency fault-tolerant control method for series-parallel hybrid power system

Abstract

The invention provides an emergency fault-tolerant control method for a series-parallel hybrid power system. The emergency fault-tolerant control method comprises the following steps that a comprehensive control unit detects whether a generator in the series-parallel hybrid power system of a vehicle breaks down or not or whether a driving motor breaks down or not; when the generator breaks down, the system is switched from a series connection mode to a series-parallel connection mode, and the vehicle is driven to run at a low speed in a first torque control mode; when the driving motor breaks down, the series-parallel hybrid power system is switched from the series mode to the series-parallel mode, and the vehicle is driven to run at a low speed in a second torque control mode; when the generator and the driving motor do not fail, the series-parallel hybrid power system is kept in a series mode, and the vehicle runs normally in a conventional mode. The method has the characteristics of low cost, accurate control and emergency fault tolerance, and can be widely applied to the field of automobiles.

Description

Technical Field

[0001] This invention relates to fault-tolerant control technology, and in particular to an emergency fault-tolerant control method for a series-parallel hybrid power system. Background Technology

[0002] The series-parallel hybrid power system, serving as the power unit for heavy-duty tracked vehicles, includes an engine-generator set, a drive motor, a coupling / transmission mechanism, a mode switch, a power battery, a supercapacitor, a cooling fan motor, a transmission oil pump motor, a water pump motor, a dust extraction fan motor, and corresponding control units. The engine-generator set and battery pack serve as the main power source and auxiliary power source, respectively. The drive motor outputs driving force to the vehicle's drive wheels via the coupling / transmission mechanism. The drive motor, power battery, and generator are coupled via a DC bus. The control units include an integrated control unit, a motor control unit, an engine control unit, and a generator control unit. The integrated control unit is the upper-level controller, while the lower-level controllers—the motor control unit, engine control unit, and generator control unit—are coupled via a local area network.

[0003] The series-parallel hybrid system configuration adds a clutch to the series configuration, enabling direct connection between the engine and the drive unit. This allows the engine and drive motor to switch between series and parallel modes. In series mode, the engine and drive motor are completely decoupled. When the vehicle enters high-power demand conditions such as high-speed cruising, obstacle crossing, or hill climbing, it switches to series-parallel mode. The engine is mechanically connected to the drive motor via a clutch or coupling mechanism. Simultaneously, the generator can provide auxiliary power generation or additional auxiliary torque as needed, achieving power coupling output and effectively improving the system's peak power and dynamic response. Furthermore, under complex transitional conditions, in addition to direct mechanical drive, a portion of the engine's power is used for power generation, achieving smooth transitions between modes and overall energy efficiency optimization.

[0004] While series-parallel hybrid systems offer greater flexibility and more precise control in vehicle operation, their inherent complexity also exposes them to a higher risk of failure. Failure of any component within a series-parallel hybrid system can trigger a chain reaction, leading to performance degradation or complete failure. Furthermore, the relatively high voltage within these systems poses a safety hazard to occupants in the event of an electrical fault.

[0005] Therefore, it is evident that there is currently no low-cost, precise control method that can provide emergency fault tolerance for series-parallel hybrid power systems. Summary of the Invention

[0006] In view of this, the main objective of the present invention is to provide a low-cost, precise, and fault-tolerant emergency control method for series-parallel hybrid power systems.

[0007] To achieve the above objectives, the technical solution proposed by this invention is as follows: The emergency fault-tolerant control method for a series-parallel hybrid power system according to the present invention includes the following steps: Step 1: The integrated control unit detects whether the generator or the drive motor in the vehicle's series-parallel hybrid system has failed. If the generator fails, proceed to step 2; if the drive motor fails, proceed to step 3; if neither the generator nor the drive motor has failed, proceed to step 4.

[0008] Step 2: When the generator fails, switch the series-parallel hybrid system from series mode to series-parallel mode and drive the vehicle at low speed using the first torque control method.

[0009] Step 3: When the drive motor fails, switch the series-parallel hybrid system from series mode to series-parallel mode, and drive the vehicle at low speed using the second torque control method.

[0010] Step 4: When neither the generator nor the drive motor malfunctions, the series-parallel hybrid system remains in series mode, and the vehicle operates normally in the conventional manner.

[0011] In summary, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention first detects whether the vehicle experiences a generator or drive motor failure. When the generator fails, the series-parallel hybrid power system operates in series-parallel mode and drives the vehicle at low speed using a first torque control method. When the drive motor fails, the series-parallel hybrid power system also operates in series-parallel mode and drives the vehicle at low speed using a second torque control method. Thus, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention employs a dual-path fault response mechanism, covering two key fault scenarios: generator failure and drive motor failure. Furthermore, the two fault scenarios are controlled separately, resulting in high control accuracy. Therefore, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention overcomes the technical bottleneck of traditional systems where "single-point failure results in shutdown," ensuring the maintenance of the basic operational capability of the transmission system under extreme fault conditions while guaranteeing zero degradation of steering function. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall process of the emergency fault-tolerant control method for the series-parallel hybrid power system described in this invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a schematic diagram of the overall flow of the emergency fault-tolerant control method for the series-parallel hybrid power system described in this invention. Figure 1 As shown, the emergency fault-tolerant control method for a series-parallel hybrid power system of the present invention includes the following steps: Step 1: The integrated control unit detects whether the generator or the drive motor in the vehicle's series-parallel hybrid system has failed. If the generator fails, proceed to step 2; if the drive motor fails, proceed to step 3; if neither the generator nor the drive motor has failed, proceed to step 4.

[0015] Step 2: When the generator fails, switch the series-parallel hybrid system from series mode to series-parallel mode and drive the vehicle at low speed using the first torque control method.

[0016] Step 3: When the drive motor fails, switch the series-parallel hybrid system from series mode to series-parallel mode, and drive the vehicle at low speed using the second torque control method.

[0017] Step 4: When neither the generator nor the drive motor malfunctions, the series-parallel hybrid system remains in series mode, and the vehicle operates normally in the conventional manner.

[0018] In summary, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention first detects whether the vehicle experiences a generator or drive motor failure. When the generator fails, the series-parallel hybrid power system operates in series-parallel mode and drives the vehicle at low speed using a first torque control method. When the drive motor fails, the series-parallel hybrid power system also operates in series-parallel mode and drives the vehicle at low speed using a second torque control method. Thus, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention employs a dual-path fault response mechanism, covering two key fault scenarios: generator failure and drive motor failure. Furthermore, the two fault scenarios are controlled separately, resulting in high control accuracy. Therefore, the emergency fault-tolerant control method for a series-parallel hybrid power system described in this invention overcomes the technical bottleneck of traditional systems where "single-point failure results in shutdown," ensuring the maintenance of the basic operational capability of the transmission system under extreme fault conditions while guaranteeing zero degradation of steering function.

[0019] In this invention, low-speed driving refers to the vehicle traveling at a speed of less than 25 km / h.

[0020] In the method of the present invention, step 2 specifically includes the following steps: Step 21: When the generator fails, the integrated control unit controls the oil pump motor to start, enabling the oil pump motor to enter the enabled state and establish the vehicle's main hydraulic pressure.

[0021] In practical applications, the establishment of the vehicle's main hydraulic pressure ensures the stability and reliability of the vehicle's hydraulic power supply, laying the foundation for the operation of subsequent transmission components.

[0022] Step 22: The integrated control unit sends a valve control command to the switching clutch and first gear brake of the mode switching unit, so that the series-parallel hybrid system switches from series mode to series-parallel mode, and the coupling mechanism of the mode switching unit is stably engaged in the first gear state.

[0023] Step 23: The drive motor adopts torque control mode: ;in, This indicates the required torque corresponding to the real-time signal from the driver's pedal. This indicates the output torque of the drive motor; Step 24: While driving the vehicle according to the torque control mode described in step 23, the drive motor also drives the engine in the opposite direction. Step 25: When the engine speed exceeds its preset ignition start value, The engine controller starts the engine, and then the engine enters torque control mode: And the drive motor stops driving; among them, This indicates the engine's output torque.

[0024] In practical applications, when the generator fails, the vehicle's driving capability comes from the emergency power supply of the power battery. In this invention, the first torque control method involves first driving the vehicle at low speed using the drive motor, and then driving the vehicle at low speed using the engine.

[0025] In the method of the present invention, after step 2 and before step 3, the fault-tolerant control method further includes the following steps: Step a: When the integrated control unit detects the steering wheel input angle, the vehicle can steer at low speeds, and the steering torque is provided by the drive motor. ;in, This indicates the steering torque.

[0026] When the generator fails, the vehicle is traveling at low speeds, and since the drive motor is not faulty, the steering torque is provided by the drive motor. Therefore, this invention can achieve zero-degradation steering when the generator fails.

[0027] In the method of the present invention, step 3 specifically includes the following steps: Step 31: When the drive motor fails, the integrated control unit controls the oil pump motor to start, enabling the oil pump motor to enter the enabled state and establish the vehicle's main hydraulic pressure.

[0028] In practical applications, the establishment of the vehicle's main hydraulic pressure ensures the stability and reliability of the vehicle's hydraulic power supply, laying the foundation for the operation of subsequent transmission components.

[0029] Step 32: The integrated control unit sends a valve control command to the switching clutch and first gear brake of the mode switching unit, so that the series-parallel hybrid system switches from series mode to series-parallel mode, and the coupling mechanism of the mode switching unit is stably engaged in the first gear state.

[0030] Step 33: The generator adopts torque control mode: ;in, This indicates the generator's output torque.

[0031] Step 34: While driving the vehicle according to the torque control mode described in step 33, the generator also tractions the engine to run.

[0032] Step 35: When the engine speed exceeds its preset ignition start value At this time, the engine controller starts the engine, and then the engine enters torque control mode: ;in, This indicates the engine's output torque.

[0033] In practical applications, when the drive motor fails, the vehicle's driving capability comes from the emergency power supply of the power battery. In this invention, the second torque control method involves first having the generator drive the vehicle at a low speed, and then having the engine drive the vehicle at a low speed.

[0034] In the method of the present invention, after step 3 and before step 4, the fault-tolerant control method further includes the following steps: Step b: When the integrated control unit detects the steering wheel input angle, the vehicle can steer at low speeds, and the engine achieves differential steering by applying braking torque to one side of the brakes: that is, .

[0035] When the drive motor fails, during low-speed vehicle operation, the engine provides steering torque to one side of the brake. This results in unequal steering torques on both sides, achieving differential steering. Therefore, this invention enables zero-degradation steering even in the event of a drive motor failure. The specific side of the brake is determined by the integrated controller based on the actual steering conditions; this determination method is existing technology and will not be elaborated upon here.

[0036] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An emergency fault-tolerant control method for a series-parallel hybrid power system, characterized in that, The fault-tolerant control method specifically includes the following steps: Step 1: The integrated control unit detects whether the generator or the drive motor in the vehicle's series-parallel hybrid system has failed. If the generator fails, proceed to Step 2; if the drive motor fails, proceed to Step 3; if neither the generator nor the drive motor has failed, proceed to Step 4. Step 2: When the generator fails, switch the series-parallel hybrid system from series mode to series-parallel mode and drive the vehicle at low speed using the first torque control method. Step 3: When the drive motor fails, switch the series-parallel hybrid system from series mode to series-parallel mode, and drive the vehicle at low speed using the second torque control method. Step 4: When neither the generator nor the drive motor malfunctions, the series-parallel hybrid system remains in series mode, and the vehicle operates normally in the conventional manner.

2. The emergency fault-tolerant control method for a series-parallel hybrid power system according to claim 1, characterized in that, The term "low-speed driving" refers to a vehicle traveling at a speed of less than 25 km / h.

3. The emergency fault-tolerant control method for a series-parallel hybrid power system according to claim 2, characterized in that, Step 2 specifically includes the following steps: Step 21: When the generator fails, the integrated control unit controls the oil pump motor to start, enabling the oil pump motor to enter the enabled state and establish the vehicle's main hydraulic pressure. Step 22: The integrated control unit sends a valve control command to the switching clutch and first gear brake of the mode switching unit, so that the series-parallel hybrid system switches from series mode to series-parallel mode, and the coupling mechanism of the mode switching unit is stably engaged in the first gear state. Step 23: The drive motor adopts torque control mode: ;in, This indicates the required torque corresponding to the real-time signal from the driver's pedal. This indicates the output torque of the drive motor; Step 24: While driving the vehicle according to the torque control mode described in step 23, the drive motor also drives the engine in the opposite direction. Step 25: When the engine speed exceeds its preset ignition start value At this time, the engine controller starts the engine, and then the engine enters torque control mode: And the drive motor stops driving; among them, This indicates the engine's output torque.

4. The emergency fault-tolerant control method for a series-parallel hybrid power system according to claim 3, characterized in that, After step 2 and before step 3, the fault-tolerant control method further includes the following steps: Step a: When the integrated control unit detects the steering wheel input angle, the vehicle can steer at low speeds, and the steering torque is provided by the drive motor. ;in, This indicates the steering torque.

5. The emergency fault-tolerant control method for a series-parallel hybrid power system according to claim 2, characterized in that, Step 3 specifically includes the following steps: Step 31: When the drive motor fails, the integrated control unit controls the oil pump motor to start, enabling the oil pump motor to enter the enabled state and establish the vehicle's main hydraulic pressure. Step 32: The integrated control unit sends a valve control command to the switching clutch and first gear brake of the mode switching unit, so that the series-parallel hybrid system switches from series mode to series-parallel mode, and the coupling mechanism of the mode switching unit is stably engaged in the first gear state. Step 33: The generator adopts torque control mode: ;in, This indicates the generator's output torque; Step 34: While driving the vehicle according to the torque control mode described in step 33, the generator also pulls the engine to run. Step 35: When the engine speed exceeds its preset ignition start value N_ig, the engine controller starts the engine, and then the engine enters torque control mode. ;in, This indicates the engine's output torque.

6. The emergency fault-tolerant control method for a series-parallel hybrid power system according to claim 5, characterized in that, After step 3 and before step 4, the fault-tolerant control method further includes the following steps: Step b: When the integrated control unit detects the steering wheel input angle, the vehicle can steer at low speeds, and the engine achieves differential steering by applying braking torque to one side of the brakes: that is, .

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